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As is usually the case with semantic arguments there is no objectively correct answer, it is a matter of convention.
But the convention here is well established, yes, the defining feature of a tank is a tracked chassis.
This is why a half-track gets it's own term, as it's half tank, half armored car. You may also encounter some tracked AA/flack guns, or tracked engineering vehicles, bulldozers, generally these may have tracks or even be built on tank chassis but are not considered tanks as they have no main gun